Summary: Biolimus A9 is a highly lipophilic Sirolimus analog (13-fold the lipophilicity of the parent drug) specifically designed for local-drug delivery. We developed immunofluorescence (IF) methods to contrast the arterial distribution of Sirolimus and Biolimus A9 after implantation of polymer-free drug-coated stents (PF DCS) in the pig coronary artery model.